Figure 10From: Novel coarse-to-fine dual scale technique for tuberculosis cavity detection in chest radiographs The second derivative of a 1D Gaussian kernel probes inside/outside contrast of the range (−σ, σ). In this example, G xx x = x 2 σ 4 − 1 σ 2 e − x 2 2 σ 2 , σ = 1.Back to article page